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A sound that was picked up is not near the current search area for MH370

The academics say it could be related to the missing plane, or just a natural event

Australian researchers released an audio recording Wednesday of an underwater sound that they say could possibly be related to the final moments of missing Malaysia Airlines Flight 370.

It's a long shot, but researchers at Curtin University near Perth, Australia, have been studying records from underwater listening devices, including those meant to monitor for signs of underwater nuclear explosions, in an effort to help find the missing plane.

"One signal has been detected on several receivers that could be related to the crash," said Alec Duncan with the university's Centre for Marine Science and Technology (CMST).

Researchers have been analyzing the very low frequency sound for weeks to see if it was "the impact of the aircraft on the water or the implosion of parts of the aircraft as it sank," Duncan said. "But (the source of the noise) is just as likely to be a natural event."

Low frequency signals can travel thousands of miles through water under favorable circumstances, at about 1 mile per second, Duncan said. But "at the moment (the sound) appears to be inconsistent with other data about the aircraft position," he said.

The search for Malaysia Airlines Flight 370 48 photos

The search for Malaysia Airlines Flight 37048 photos

Relatives of passengers from Malaysia Airlines Flight MH370 console each other outside the Malaysia Airlines office in Subang, Malaysia, on Thursday, February 12. Protesters demanded that the airline withdraw the statement made in January that all the passengers aboard the plane are dead. The plane, which disappeared on March 8, has not been found.

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The search for Malaysia Airlines Flight 37048 photos

A policewoman watches a couple whose son was on board the missing Malaysia Airlines Flight 370 cry outside the airline's office building in Beijing after officials refused to meet with them on June 11, 2014. The search for the missing plane has been ongoing since early 2014.

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The search for Malaysia Airlines Flight 37048 photos

Members of the media scramble to speak with Azharuddin Abdul Rahman, director general of Malaysia's Civil Aviation Department, at a hotel in Kuala Lumpur, Malaysia, on May 27. Data from communications between satellites and missing Malaysia Airlines Flight 370 was released the day before, more than two months after relatives of passengers say they requested that it be made public.

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The search for Malaysia Airlines Flight 37048 photos

Operators aboard the Australian ship Ocean Shield move Bluefin-21, the U.S. Navy's autonomous underwater vehicle, into position to search for the jet on April 14.

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The search for Malaysia Airlines Flight 37048 photos

A member of the Royal New Zealand Air Force looks out of a window while searching for debris off the coast of western Australia on April 13.

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The search for Malaysia Airlines Flight 37048 photos

The Echo moves through the waters of the southern Indian Ocean on April 12.

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The search for Malaysia Airlines Flight 37048 photos

A Royal Australian Air Force AP-3C Orion, on a mission to drop sonar buoys to assist in the search, flies past the Australian vessel Ocean Shield on April 9.

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The search for Malaysia Airlines Flight 37048 photos

A relative of a missing passenger cries at a vigil in Beijing on April 8.

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The search for Malaysia Airlines Flight 37048 photos

Australian Defense Force divers scan the water for debris April 7, in the southern Indian Ocean.

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The search for Malaysia Airlines Flight 37048 photos

A towed pinger locator is readied to be deployed April 7 off the deck of the Australian vessel Ocean Shield.

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The search for Malaysia Airlines Flight 37048 photos

A member of the Royal New Zealand Air Force looks at a flare in the Indian Ocean during search operations on April 4.

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The search for Malaysia Airlines Flight 37048 photos

A member of the Japanese coast guard points to a flight position data screen while searching for debris from the missing jet on April 1.

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The search for Malaysia Airlines Flight 37048 photos

A woman prepares for an event in honor of those aboard Flight 370 on March 30, in Kuala Lumpur, Malaysia.

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The search for Malaysia Airlines Flight 37048 photos

A Royal New Zealand Air Force member launches a GPS marker buoy over the southern Indian Ocean on March 29.

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The search for Malaysia Airlines Flight 37048 photos

The sole representative for the families of Flight 370 passengers leaves a conference at a Beijing hotel on March 28, after other relatives left en masse to protest the Malaysian government's response to their questions.

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The search for Malaysia Airlines Flight 37048 photos

A member of the Royal Australian Air Force is silhouetted against the southern Indian Ocean during the search for the missing jet on March 27.

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The search for Malaysia Airlines Flight 37048 photos

Flight Lt. Jayson Nichols looks at a map aboard a Royal Australian Air Force aircraft during a search on March 27.

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The search for Malaysia Airlines Flight 37048 photos

People in Kuala Lumpur light candles during a ceremony held for the missing flight's passengers on March 27.

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The search for Malaysia Airlines Flight 37048 photos

Malaysian Prime Minister Najib Razak, center, delivers a statement about the flight on March 24 in Kuala Lumpur. Razak's announcement came after the airline sent a text message to relatives saying it "deeply regrets that we have to assume beyond any reasonable doubt that MH 370 has been lost and that none of those onboard survived."

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The search for Malaysia Airlines Flight 37048 photos

Grieving relatives of missing passengers leave a hotel in Beijing on March 24.

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The search for Malaysia Airlines Flight 37048 photos

Ground crew members wave to a Japanese Maritime Defense Force patrol plane as it leaves the Royal Malaysian Air Force base in Subang, Malaysia, on March 23. The plane was heading to Australia to join a search-and-rescue operation.

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The search for Malaysia Airlines Flight 37048 photos

A passenger views a weather map in the departures terminal of Kuala Lumpur International Airport on March 22.

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The search for Malaysia Airlines Flight 37048 photos

A Chinese satellite captured this image, released on March 22, of a floating object in the Indian Ocean, according to China's State Administration of Science. It is a possible lead in the search for the missing plane. Surveillance planes are looking for two objects spotted by satellite imagery in remote, treacherous waters more than 1,400 miles from the west coast of Australia.

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The search for Malaysia Airlines Flight 37048 photos

Satellite imagery provided by the Australian Maritime Safety Authority on March 20, shows debris in the southern Indian Ocean that could be from Flight 370. The announcement by Australian officials that they had spotted something raised hopes of a breakthrough in the frustrating search.

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The search for Malaysia Airlines Flight 37048 photos

Another satellite shot provided by the Australian Maritime Safety Authority shows possible debris from the flight.

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The search for Malaysia Airlines Flight 37048 photos

A distraught relative of a missing passenger breaks down while talking to reporters at Kuala Lumpur International Airport on March 19.

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The search for Malaysia Airlines Flight 37048 photos

A relative of a missing passenger tells reporters on March 18 in Beijing about a hunger strike to protest authorities' handling of information about the missing jet.

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The search for Malaysia Airlines Flight 37048 photos

U.S. Navy crew members assist in search-and-rescue operations March 16, in the Indian Ocean.

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The search for Malaysia Airlines Flight 37048 photos

Members of the Chinese navy continue search operations on March 13. The search area for Flight 370 has grown wider. After starting in the sea between Malaysia and Vietnam, the plane's last confirmed location, efforts are expanding west into the Indian Ocean.

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The search for Malaysia Airlines Flight 37048 photos

A Vietnamese military official looks out an aircraft window during search operations March 13.

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The search for Malaysia Airlines Flight 37048 photos

Malaysian air force members look for debris on March 13 near Kuala Lumpur.

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The search for Malaysia Airlines Flight 37048 photos

Relatives of missing passengers wait for the latest news at a hotel in Beijing on March 12.

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The search for Malaysia Airlines Flight 37048 photos

Indonesian air force officers in Medan, Indonesia, examine a map of the Strait of Malacca on March 12.

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A member of the Vietnamese air force checks a map while searching for the missing plane on March 11.

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The search for Malaysia Airlines Flight 37048 photos

Vietnam air force Col. Le Huu Hanh is reflected on the navigation control panel of a plane that is part of the search operation over the South China Sea on March 10.

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The search for Malaysia Airlines Flight 37048 photos

A Vietnamese air force plane found traces of oil that authorities had suspected to be from the missing Malaysia Airlines plane, the Vietnamese government online newspaper reported March 8. However, a sample from the slick showed it was bunker oil, typically used to power large cargo ships, Malaysia's state news agency, Bernama, reported on March 10.

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A U.S. Navy Seahawk helicopter lands aboard the USS Pinckney to change crews before returning to search for the missing plane March 9, in the Gulf of Thailand.

Italian tourist Luigi Maraldi, who reported his passport stolen in August, shows his current passport during a news conference at a police station in Phuket island, Thailand, on March 9. Iranians Pouri Nourmohammadi and Delavar Seyed Mohammad Reza were identified by Interpol as the two men who used stolen passports to board the flight. But there's no evidence to suggest either was connected to any terrorist organizations, according to Malaysian investigators. Malaysian police believe Nourmohammadi was trying to emigrate to Germany using the stolen Austrian passport.

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Vietnamese air force crew stand in front of a plane at Tan Son Nhat airport in Ho Chi Minh City on March 9 before heading out to the area between Vietnam and Malaysia where the airliner vanished.

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Buddhist monks at Kuala Lumpur International Airport offer a special prayer for the missing passengers on March 9.

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The Chinese navy warship Jinggangshan prepares to leave Zhanjiang Port early on March 9 to assist in search-and-rescue operations for the missing Malaysia Airlines flight. The Jinggangshan, an amphibious landing ship, is loaded with lifesaving equipment, underwater detection devices and supplies of oil, water and food.

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Members of a Chinese emergency response team board a rescue vessel at the port of Sanya in China's Hainan province on March 9. The vessel is carrying 12 divers and will rendezvous with another rescue vessel on its way to the area where contact was lost with Malaysia Airlines Flight 370.

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The rescue vessel sets out from Sanya in the South China Sea on March 9.

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Malaysian Prime Minister Najib Razak, center, arrives to meet family members of missing passengers at the reception center at Kuala Lumpur International Airport on March 8.

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A relative of two missing passengers reacts at their home in Kuala Lumpur on March 8.

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Chinese police at the Beijing airport stand beside the arrival board showing delayed Flight 370 in red on March 8.

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Malaysia Airlines Group CEO Ahmad Juahari Yahya, front, speaks during a news conference on March 8 at a hotel in Sepang. "We deeply regret that we have lost all contacts" with the jet, he said.

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EXPAND GALLERY

Just Watched

Official: MH370 is not in ping area

Just Watched

Officials: Flight 370 not in search area

That's because researchers at Curtin University believe the sound came from an area thousands of miles to the northwest of the current search area in the southern Indian Ocean. And even then, they haven't been able to pinpoint the source.

Duncan says his team has calculated an "uncertainty box" for the signal's origin. It's area that stretches some 2,485 miles in length from southeast to northwest across the Indian Ocean, and spans some 124 to 186 miles in width at its widest point.

The center of the long, narrow box is south of the tip of India, as shown in a map released Wednesday.

The university on Wednesday released an audio clip captured by one of the listening devices, off of Perth. Duncan says his team has sped up the recording 10 times to make it audible to the human ear.

It also shared charts of acoustic signal plots showing what various devices detected.

Searching in the right place?

The search for the missing Malaysia Airlines flight continues to focus along an arc hundreds of kilometers long, the area where investigators believe the Boeing 777 ran out of fuel, about 1,000 miles off the coast of Western Australia.

Martin Dolan, the chief commissioner with the Australian Transport Safety Bureau (ATSB), the organization leading the search into MH370 at the request of Malaysia, says an international team of experts continues to review the analysis of Inmarsat satellite data and aircraft performance.

In a television exclusive, Dolan told CNN's "Erin Burnett OutFront" he remains confident the final resting place of MH370 is somewhere along that arc, the so-called "partial handshake" with the satellite:

"We've seen all the data. We've seen all the calculations. We are reviewing the calculations and are also developing our own model to cross check and verify that information," Dolan told Burnett.

When asked last week about the underwater sound being analyzed by the team at Curtin University, along with Geoscience Australia, a government agency, Dolan was skeptical.

"We think that those detections may have been interesting from the point of view of the direction they came, but other characteristics make it unlikely that they are associated with MH370," he said. The ATSB first referenced these signals in a document posted on its website on May 26.

Just Watched

Malaysia missing plane data released

As was the case with the Inmarsat satellite -- a communications satellite whose data was analyzed by Malaysia Airlines MH370 investigators as a navigational aide -- the analysis of the underwater signals involves the use of technology for a different purpose than its original intent.

One of the devices, operated by Curtin University and located some 12 miles off Perth, is designed to listen to whales and other marine life. The other is for signs of underwater nuclear explosions, one of 11 operated worldwide by the U.N.-chartered Comprehensive Test Ban Treaty Organization (CTBTO) as part of the International Monitoring System.

Early in the search for Malaysia Flight 370, the United Nations reported it had not detected any explosions or plane crashes on land or water from its sensors around the globe. But the recent efforts involve pairing CTBTO data with other sources to see what can be gleaned, officials said.

"One can always be hopeful," said Mark Prior, a seismic acoustic analyst with the CTBTO.

The CTBTO's hydro-acoustic stations detect low frequency sound in the 0-100 Hz range, and can't detect black box "pings" in the 30-40 kHz range, officials said. "It's possible (to detect a plane crash), but the circumstances that would allow it would have to be very particular," said Prior.

Prior said some of those circumstances might include a sloping sea bed. Another possible scenario: the origin of the sound would need to be near the listening device.

The CTBTO's system near Cape Leeuwin, the southwestern-most point of Australia, regularly captures signals of ice breaking noise from Antarctica and seismic activity from Indonesia, he said. "There are other scenarios that would allow (the hydrophones to detect a crash). But it's not certain if there was an impact we would detect it," Prior said.

Attempts were made following the 2009 crash of Air France 447 in the southern Atlantic Ocean to see if underwater listening devices had detected the plane's impact. No data could be found.

Years later, after the plane was located, CTBTO again checked its data, and still was not able to identify signals related to the crash.